The Broadcom BCM57761 controller is a special type that has full spec support for what Broadcom calls EthernetAV. Broadcom also calls it BroadSync HD. So far, this chip is the best, most compliant controller to date.
Trouble is... No one is making any PCIe NIC cards with it yet. Some mac laptops have it built-in.
I tried searching for new motherboards, but no one seems to sort by LAN chipset.